
.login_window{
    width: 400px;
    height: 300px;
    background-color: rgba(143,143,143,0.4);

    padding: 20px;
    box-sizing: border-box;

    /*绝对定位 让元素垂直 水平居中*/
    position: absolute;
    top: 50%;
    margin-top: -150px;
    left: 50%;
    margin-left: -200px;

    /*添加阴影、圆角*/
    box-shadow: 0 0 10px white;
    border-radius: 10px;

    text-align: center;
}

.login_window > dt{
    padding: 30px 0;
    font-size: 20px;
    color: white;
    font-weight: bold;
    text-shadow: 0 0 5px gray;
}

.login_window input{
    display: block;
    width: 70%;
    height: 35px;
    /*目的 让输入的文字 不顶头*/
    padding: 0 10px;
    /*让块级元素居中*/
    margin: 10px auto;
    border-radius: 5px;
    background-color: rgba(255,255,255,0.3);
    box-shadow: 0 0 3px white;
    color: white;
    font-size: 16px;
}

.login_window .login_button{
    display: block;
    width: 50%;
    height: 30px;
    background-color: rgba(68,68,68,0.3);
    color: white;
    border-radius: 10px;
    margin: 35px auto 0;
    font-size: 16px;
}

.login_window .login_to_register_button{
    text-decoration: none;
    color: gray;
    font-size: 12px;
    display: block;
    width: 50%;
    margin: 0 auto;
    text-align: right;
    padding-right: 20px;
    box-sizing: border-box;
}